<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 300px;
            height: 300px;
            background: red;
            display: none;
        }
    </style>
</head>
<body>
    <button>按钮</button>
    <div class="box"></div>
    <script src="https://cdn.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js" integrity="sha384-nvAa0+6Qg9clwYCGGPpDQLVpLNn0fRaROjHqs13t4Ggj3Ez50XnGQqc/r8MhnRDZ" crossorigin="anonymous"></script>
    <script>
        //  $('button').click(function(){
        //     //  $('.box').show();
        //     $('.box').slideDown();
        //  })

        $('button').click(function(){
            //  $('.box').show();
            $('.box').toggle('slide');
         })
    </script>
</body>
</html>